WO2019156138A1

WO2019156138A1 - Vehicle-mounted antenna device

Info

Publication number: WO2019156138A1
Application number: PCT/JP2019/004332
Authority: WO
Inventors: 優清水; 剛小森; 雄三原田
Original assignee: 株式会社ヨコオ
Priority date: 2018-02-08
Filing date: 2019-02-07
Publication date: 2019-08-15
Also published as: US20210044006A1; JP7152431B2; CN111684651A; CN111684651B; US11881615B2; JPWO2019156138A1; JP2022185043A; JP7450682B2; CN116845568A

Abstract

A capacity loaded element (70) is provided at a position distant from a camera (60). When the capacity loaded element (70) is divided into a short distance-side part (75) and a long distance- side part (74) on the basis of the distance from the camera (60), in the short distance-side part (75), the length in the height direction of a first section (76) overlapping the camera (60) in top view and/or side view is made shorter than that of a second section (77) not overlapping the camera (60) in top view and/or side view.

Description

In-vehicle antenna device

The present invention relates to a vehicle-mounted antenna device.

There is a low-profile antenna device that is mounted on the rooftop of a vehicle and has a fin shape with reduced fluid resistance. Because of its shape, it is also called “shark fin antenna” or “dolphin antenna”.

Inside a vehicle-mounted antenna device called a shark fin antenna, not only a plurality of antennas but also various electronic devices can be accommodated. For example, Patent Document 1 discloses an in-vehicle antenna device incorporating a camera that captures the rear of a vehicle body.

JP 2016-1116048 A

Because it is mounted on the rooftop of a vehicle, the size of the in-vehicle antenna device is restricted. There is also a need to accommodate a plurality of electrical and electronic devices such as antennas and cameras in a shape with reduced fluid resistance, and to accommodate as much influence as possible. Therefore, various devices are required for the vehicle-mounted antenna device. In particular, improvement in antenna gain is always required.

The problem to be solved by the present invention is to provide a technique for improving the gain of an antenna in a vehicle-mounted antenna device that accommodates an antenna and a camera.

An aspect of the present invention includes an antenna, a camera, and a case that accommodates the antenna and the camera, and the antenna includes a capacitive loading element provided at a position separated from the camera, and the capacitive loading When the element is divided into a short-distance side portion and a long-distance side portion based on the distance from the camera, the first portion that overlaps the camera in the top view and / or the side view is included in the short-distance side portion. The vehicle-mounted antenna device has a shorter length in the height direction than the second portion that does not overlap the camera in a top view and / or a side view.

According to this aspect, the capacitive loading element and the camera are electromagnetically coupled as compared with the case where the first portion of the capacitive loading element has the same or longer length in the height direction than the second portion. It is possible to reduce the electromagnetic influence of the generated capacitive loading element from the camera, and the gain of the antenna can be improved.

The capacitive loading element is arranged in a direction in which the longitudinal direction is along the optical axis direction of the camera, and the length in the longitudinal direction of the capacitive loading element is longer than the length in the longitudinal direction of the camera. Good.

According to this, it is possible to arrange the capacity loading element having a length in the longitudinal direction longer than the length in the longitudinal direction of the camera in a direction in which the longitudinal direction is along the optical axis direction of the camera.

The capacitive loading element may be a vehicle-mounted antenna device having a meander-like wiring shape in which meandering is repeated in the longitudinal direction, and the parallel direction of the meandering parallel wiring is arranged in the direction along the height direction.

According to this, a capacitive loading element having a meandering wiring shape in which the repeating direction of the meandering is the direction along the longitudinal direction and the parallel direction of the meandering parallel wiring is oriented along the height direction can be obtained. . Thereby, a capacity | capacitance loading element can be comprised compactly, ensuring sufficient electric length.

The first part may be a vehicle-mounted antenna device in which the length in the height direction is gradually shortened as the distance from the second part increases.

According to this, the length in the height direction of the first part can be gradually shortened as the distance from the second part increases. Accordingly, it is possible to further reduce the electromagnetic influence that the capacitive loading element receives from the camera as compared with the case where the length in the height direction of the first part is not gradually shortened as the distance from the second part increases. The antenna gain can be further improved.

In the first position and the second position of the first part, the first position is relatively closer to the second part than the second position, and the length of the first position in the height direction is the first position. It is good also as a vehicle-mounted antenna apparatus longer than the height direction length of 2 positions.

According to this, in the first part, the length in the height direction of the first position relatively close to the second part is made longer than the length in the height direction of the second position relatively far from the second part. be able to. As a result, it is possible to further reduce the electromagnetic influence of the capacitive loading element from the camera compared to when the height of the first position is not longer than the length of the second position. Thus, the antenna gain can be further improved.

The capacitive loading element may be an in-vehicle antenna device provided at a higher position than the camera.

According to this, the capacity loading element can be provided at a position higher than the camera. Thereby, the antenna gain can be further improved as compared with the case where the capacitive loading element is not provided at a position higher than the camera.

The vehicle-mounted antenna device may further include an inner case accommodated in the case, and the capacitive loading element and the camera may be disposed in a space between the case and the inner case.

According to this, since the case and the inner case are covered with a double layer as compared with the case where the inner case is not provided, the waterproofness and dustproofness with respect to the electronic devices and the like disposed inside the inner case are increased. Further, the antenna gain can be further improved by increasing the height of the mounting position compared to when the capacitive loading element is provided inside the inner case. In addition, when the inner case is not provided, it is necessary to manage electronic devices etc. arranged inside the case with different product numbers if the case color is different. It is possible to share the part numbers of the arranged electronic devices, etc., and management becomes easy. In addition, the inner case can partition the accommodation space in the case, and the antenna, the capacity loading element, and the camera can be efficiently arranged. The inner case may be a structure that supports the capacitive loading element and the camera.

The camera may be a camera that captures the rear of the vehicle when installed on the roof of the vehicle, and the first part may be an in-vehicle antenna device located on the rear side of the vehicle with respect to the second part.

According to this, it can be set as the structure which mounts a camera so that the vehicle rear may be image | photographed from the roof of a vehicle.

The camera may be a vehicle-mounted antenna device having a camera body and a metal casing that houses the camera body.

According to this, the electromagnetic influence generated from the camera body can be reduced by the metal casing.

The camera cable may be an in-vehicle antenna device including a magnetic material.

According to this, the noise that the camera can give to the antenna can be reduced.

The camera cable may be an in-vehicle antenna device in which an external conductor is connected to the ground.

According to this, the noise given to the antenna by the camera can be further reduced.

The figure which shows the use condition of the vehicle-mounted antenna apparatus. The exploded view which shows the structural example of the vehicle-mounted antenna apparatus. It is a figure which shows the structural example of the vehicle-mounted antenna apparatus, Comprising: The internal structure figure seen from the left side surface of the apparatus. It is a figure which shows the structural example of the vehicle-mounted antenna apparatus, Comprising: The internal structure figure which looked at the apparatus from the top. The perspective rear view which shows the structural example of the vehicle-mounted antenna apparatus. The left view which shows the structural example of a capacity | capacitance loading element. The graph which shows the characteristic of the horizontal surface average gain in a vehicle-mounted antenna apparatus. It is a figure which shows the structural example of the vehicle-mounted antenna apparatus, Comprising: The internal structure figure seen from the left side surface of the apparatus. The graph which shows the characteristic of the horizontal plane average gain in the vehicle-mounted antenna apparatus of the state which started the camera. The fragmentary perspective view which looked at the cable holder and its periphery from the upper side. The figure which looked at the cable holder and its periphery from the lower side. It is a figure for demonstrating the structural example in the modification 2 of a vehicle-mounted antenna apparatus, Comprising: The internal structure figure seen from the left side surface of the apparatus. It is a figure for demonstrating the structural example in the modification 3 of a vehicle-mounted antenna apparatus, Comprising: The internal structure figure seen from the left side surface of the apparatus. The figure which shows the relationship between a separation distance and a horizontal surface average gain. The figure which shows an example of the shape change of the capacity | capacitance loading element based on a separation distance. The graph which shows the horizontal surface average gain of the vehicle-mounted antenna apparatus made into the capacity | capacitance loading element for DAB wave band reception.

Hereinafter, an example of an embodiment to which the present invention is applied will be described, but it is needless to say that an embodiment to which the present invention can be applied is not limited to the following embodiment.

The direction definition in the following description is as follows.
The front / rear / left / right / up / down directions of the in-vehicle antenna device 10 are the same as the front / rear, left / right, up / down directions of the vehicle when mounted on the vehicle. The horizontal direction may be referred to as the horizontal direction and the vertical direction may be referred to as the vertical direction. In order to facilitate understanding of the direction, the front-rear direction, the left-right direction, and the up-down direction are indicated by line segments with arrows in the figure. The intersection of each line segment with an arrow does not mean the coordinate origin. Also. The appearance of the in-vehicle antenna device 10 of the present embodiment is designed so that the front is tapered and the width on the left and right is gradually narrowed upward from the mounting surface to the vehicle. It helps to understand.

FIG. 1 is a diagram showing a use state of the vehicle-mounted antenna device 10 in the present embodiment. A portion surrounded by an ellipse of a thin line in FIG. 1 is enlarged and shown at the top of FIG. Moreover, the white thick arrow in FIG. 1 has shown the front-back direction of the vehicle, and the black thin arrow has shown the front-back direction of the vehicle-mounted antenna apparatus 10, the left-right direction, and the up-down direction.

The in-vehicle antenna device 10 is, for example, an antenna device mounted on the rear upper surface of the roof 5 of the vehicle 3 that is a passenger car. The external shape of the vehicle-mounted antenna device 10 has a fin shape that rectifies traveling wind during vehicle traveling and reduces fluid resistance. Specifically, when viewed from above, the exterior of the vehicle-mounted antenna device 10 tapers forward, and the left and right widths increase toward the rear. Further, when viewed from the back, the width is designed so that the left and right widths gradually narrow from the mounting surface to the vehicle 3 upward. Of course, the appearance design is not limited to this.

2 to 5 are diagrams showing a configuration example of the in-vehicle antenna device 10.
FIG. 2 is an exploded view showing a configuration example of the vehicle-mounted antenna device 10.
FIG. 3 is an internal structural view of the vehicle-mounted antenna device 10 as viewed from the left side, and for the sake of easy understanding, a vertical cross-sectional guide at the left and right center of the outer case 12 is indicated by a broken line.
FIG. 4 is an internal structural view of the apparatus with the outer case 12 removed as viewed from above.
FIG. 5 is a transparent rear view of the vehicle-mounted antenna device 10, and the outline of the outer case is indicated by a broken line.

The on-vehicle antenna device 10 of the present embodiment includes an outer case 12, an antenna base 30, and a pad 40.

The outer case 12 is a case made of a radio wave permeable synthetic resin that mainly forms an accommodation space that opens downward.

The antenna base 30 includes a resin base 31 and a metal base 32.
The resin base 31 is a base part for connecting the respective parts of the apparatus, and is made of an insulating synthetic resin. A metal base 32 is assembled to the resin base 31. Then, the vehicle-mounted antenna device 10 can be fixed to the roof 5 by inserting the vehicle connecting portion 36 provided on the lower surface of the metal base 32 into the vehicle through the attachment hole provided in the roof 5 of the vehicle 3. A through hole is provided inside the vehicle connecting portion 36, and a camera cable 18 described later is guided from the in-vehicle antenna device 10 into the vehicle. Of course, elements other than these can be appropriately mounted on the resin base 31. For example, when a plurality of antennas are mounted on the vehicle-mounted antenna device 10, a main body or an antenna substrate of each antenna can be mounted.
A configuration in which the entire antenna base 30 is made of metal is also possible. Further, the camera cable 18 may be drawn into the vehicle 3 through a hole other than the through hole of the vehicle connecting portion 36. A cable holder 21 described later is attached to the antenna base 30 (see FIG. 10).

And the vehicle-mounted antenna device 10 forms an internal space having a certain waterproof property and dustproof property by assembling the outer case 12 and the resin base 31 with the soft insulating pad 40 interposed therebetween.

The in-vehicle antenna device 10 includes an inner case 20, an antenna 50, and a camera 60 in this internal space. The antenna 50 includes a helical element 52, an upper terminal terminal 54, a lower terminal terminal 56, an antenna substrate 57, and a capacitive loading element 70.

The inner case 20 is a second case that partitions the accommodation space formed by the outer case 12, and is made of a radio wave permeable synthetic resin. The inner case 20 is screwed to the upper surface of the resin base 31 with the pad 40 interposed therebetween, and the helical element 52, the upper terminal terminal 54, and the lower terminal terminal 56 are disposed therein. That is, the helical element 52, the upper terminal terminal 54, and the lower terminal terminal 56 are disposed in a highly waterproof / dustproof space covered with the outer case 12 and the inner case 20. Moreover, since the accommodation space in the outer case 12 can be partitioned by the inner case 20, the antenna 50, the capacity loading element 70, and the camera 60 can be efficiently arranged. When the in-vehicle antenna device 10 does not include the inner case 20, the color of the outer case 12 must be different, and the electronic devices and the like arranged in the outer case 12 with different product numbers had to be managed. When the inner case 20 is provided, the product numbers of electronic devices and the like arranged inside the outer case 12 can be made common and management becomes easy.

The helical element 52 is formed by winding a conductor in a spiral shape. One end of the helical element 52 is connected to the upper terminal terminal 54 and the other end is connected to the lower terminal terminal 56 to be in an electrically conductive state. The helical element 52 may be attached to a substrate installed perpendicular to the antenna substrate 57 in a state where the axial direction of the spiral is the vertical direction. The upper terminal terminal 54 is screwed to the capacitive loading element 70 with the inner case 20 interposed therebetween, and is in an electrically conductive state. The lower terminal terminal 56 is inserted into the board connection terminal 38 of the antenna board 57 provided on the upper surface of the metal base 32, and is in electrical conduction with the antenna board 57. The antenna 50 in the present embodiment is an antenna that receives AM / FM broadcasts, but may be other types of antennas, and the antenna structure can be appropriately changed accordingly.

The camera 60 includes a camera body 62 and a metal housing 64 and is attached to the rear portion of the inner case 20 via the waterproof packing 15. A camera 60 is installed in a space between the outer case 12 and the inner case 20. Furthermore, the camera 60 is attached to the center of at least one of the resin base 31 and the metal base 32 in the left-right direction. The optical axis direction of the camera 60 is set so that the vehicle rear side is photographed when the vehicle-mounted antenna device 10 is installed on the roof 5 of the vehicle 3. The camera 60 takes pictures from the small window 13 provided in the rear part of the outer case 12 (see FIGS. 1 and 3).

A bracket can be appropriately added between the waterproof packing 15 and the inner case 20. The optical axis direction of the camera 60 can be adjusted by preparing various bracket shapes and replacing them with appropriate types according to the vehicle type of the vehicle 3 to which the vehicle-mounted antenna device 10 is mounted. Moreover, although the small window 13 is an opening provided in the outer case 12 in the present embodiment, it may be realized as a transparent portion by a colorless transparent resin or the like.

The camera body 62 includes an image sensor, an optical element such as a lens, an electronic shutter, an image processing circuit, an image signal generation circuit, and the like, and generates and outputs a captured image signal. The image signal is transmitted to the camera cable 18 via the cable socket 16 attached to the front of the camera body 62. The camera cable 18 is drawn into the vehicle body of the vehicle through the through hole of the vehicle connecting portion 36, and the image taken by the camera 60 is used for display on the back monitor of the vehicle.

The metal housing 64 is a metal body that covers mainly the front side (the side attached to the inner case 20; the side opposite to the photographing direction) of the camera body 62, and is an electric device such as an image sensor, an electronic shutter, and an image processing circuit. Emission of electromagnetic waves generated from the electronic elements to the outside of the camera 60 is suppressed. By covering the camera body 62 with the metal housing 64, interference with the antenna 50 due to electromagnetic waves emitted from the camera body 62 is suppressed.

The capacitive loading element 70 of the antenna 50 is an element that adds a ground capacitance to the helical element 52, and is located above the inner case 20, in a space between the outer case 12 and the inner case 20 and higher than the camera 60. Is provided. Specifically, the capacitive loading element 70 is partially spaced apart from the camera 60 in a longitudinal direction so that a part of the capacitive loading element 70 overlaps the camera 60 when viewed from the top, but does not overlap the camera 60 when viewed from the side. Are provided along the optical axis direction of the camera 60.

If the longitudinal length (length in the longitudinal direction) is compared, the capacity loading element 70 is longer than the longitudinal length of the camera 60. By providing the capacitive loading element 70 on the upper outer side of the inner case 20, it is possible to increase the mounting position and improve the antenna gain as compared with the case where the capacitive loading element 70 is provided inside the inner case 20. Further, since the capacitive loading element 70 is provided at a position higher than the camera 60, the antenna gain can be further improved as compared with the case where the capacitive loading element 70 is not provided at a position higher than the camera 60. it can.

The capacity loading element 70 of the present embodiment includes a right element 71 and a left element 72, and an element connecting portion 73 that connects both of them. The element connecting portion 73 is screwed to the upper surface of the inner case 20 so that the capacitive loading element 70 is fixed to the inner case 20 and is electrically connected to the upper terminal terminal 54 of the antenna 50 via the screw. It is said.

The right element 71 and the left element 72 are mirror-symmetrical on the left and right. In the present embodiment, the right element 71 and the left element 72 have a meandering wiring shape that meanders along the optical axis direction of the camera 60, and the parallel direction of the meandering parallel wiring is an orientation along the height direction. It has become. Since the right element 71 and the left element 72 are connected by the element connecting portion 73, it can be said that the capacity loading element 70 of this embodiment has a meander shape as a whole. As a result, it is possible to make the capacitive loading element 70 compact while ensuring a sufficient electrical length for the capacitive loading element 70.

The number of meander-shaped meandering repeats and the electrical length of the wiring can be set as appropriate. The right element 71 and the left element 72 are preferably mirror-symmetrical on the left and right, but may not necessarily be mirror-symmetrical.

FIG. 6 is a left side view illustrating a configuration example of the capacitive loading element 70.
When the right element 71 and the left element 72 are divided into the short distance side portion 75 and the long distance side portion 74 based on the distance from the camera 60, the short distance side portion 75 includes the first portion 76 and the second portion 77. And have. The first part 76 is a part that overlaps the camera 60 when viewed from above but does not overlap the camera 60 when viewed from side. The second portion 77 is a portion that is on the vehicle front side of the first portion 76 and does not overlap the camera 60 in either a top view or a side view. The first portion 76 is set to have a shorter length in the height direction than the second portion 77.

Specifically, when comparing the length of the parallel wiring corresponding to the wiring portion in the vertical direction in the meander shape of the short distance side portion 75, the length in the height direction of the second portion 77 (in FIG. The length in the height direction of the first portion 76 (represented by H1d, H1e, and H1f in FIG. 6 as a representative) is shorter than the lengths H2a, H2b, and H2c. . Furthermore, if attention is paid to each parallel wiring portion in the first portion 76, the length in the height direction increases as the distance from the second portion 77 increases. In the present embodiment, the first portion 76 is formed such that the length in the height direction gradually decreases as the distance from the second portion 77 increases (H1d> H1e> H1f in FIG. 6).

FIG. 7 is a graph showing the characteristics of the horizontal plane average gain in the vehicle-mounted antenna device 10 of the present embodiment. A solid line shows the gain by the vehicle-mounted antenna device 10 of the present embodiment. A broken line is a comparative example. As shown in FIG. 7, the comparative example is a capacitive loading element 70 </ b> X configured such that a portion corresponding to the first portion 76 of the vehicle-mounted antenna device 10 overlaps the camera 60 in both a top view and a side view.

The capacitive loading element 70 of the in-vehicle antenna device 10 of the present embodiment is designed so as to be as far away from the camera 60 as possible, and so that the portion overlapping the camera 60 is as small as possible when viewed from the top or side. . As a result, the electromagnetic influence by the camera body 62 that is provided outside with the metal housing 64 provided is reduced, and the horizontal plane average gain is higher than that of the comparative example in the entire frequency range indicated by the horizontal axis of the graph.

Next, countermeasures against noise that the camera 60 can give to the antenna 50 will be described.
FIG. 8 is a diagram for explaining noise countermeasures of the camera 60. In FIG. 8, in the internal structure diagram of the vehicle-mounted antenna device 10 shown in FIG. 3, a part of the inner case 20 is further cut away to show the periphery of the cable socket 16. The cross section of the cut out inner case 20 is shown as a case cross section 20d. Characteristically, the noise countermeasure of the camera 60 is not a countermeasure for reducing the noise received by the camera 60. Noise countermeasures are not necessary for the operation of the camera 60 itself. This is a measure for applying noise generated by the camera 60 to the camera 60 side for the antenna 50.

Although not shown in FIG. 2, as shown in FIG. 8, the camera cable 18 includes a branch line 18a having a terminal 18b at the tip. The camera cable 18 is a coaxial cable including a magnetic material.

The branch line 18 a is connected to the outer conductor of the camera cable 18. The terminal 18 b is screwed to a conductive rib 19 that is electrically connected to the metal base 32. Therefore, the outer conductor of the camera cable 18 is connected to the ground.

Since the camera cable 18 includes a magnetic material, it can be said to be a magnetic material cable.

Since the camera cable 18 has the above-described characteristic configuration, noise countermeasures for the antenna 50 are realized. The effect of this noise countermeasure will be described with reference to FIG. FIG. 9 is a graph showing the degree of noise improvement in the FM waveband when the camera 60 is activated. A difference in camera noise when various cables are used is shown as a noise improvement degree with respect to camera noise when a coaxial cable not including a magnetic material and not connected to the ground is used. When the noise improvement degree is positive, it indicates that the reception of noise is suppressed, and the larger the value, the better the noise from the camera as an antenna noise countermeasure.

In Fig. 9, the solid line indicates the noise improvement when the outer conductor of the coaxial cable not including the magnetic material is connected to the ground. The dotted line indicates the degree of noise improvement when using a magnetic cable that is not connected to the ground because there is no branch line 18a. The broken line indicates the degree of noise improvement when the camera cable 18 of the present embodiment, which is a magnetic cable connected to the ground by the branch line 18a, is used.

As can be seen from the dotted line graph, even the magnetic cable that is not connected to the ground can suppress the reception of noise. Further, as can be seen from the solid line graph, even a coaxial cable that does not include a magnetic material can suppress reception of noise by being connected to the ground. As can be seen from the broken line graph, the camera cable 18 of the present embodiment using the magnetic cable connected to the ground has the best noise improvement, and the influence of noise that can be mixed into the received signal of the antenna 50 is reduced most. can do.

In addition to noise countermeasures for the camera cable 18, a cable holder 21 as shown in FIG. 8 is provided inside the inner case 20 for the convenience of wiring by the operator. 10 and 11 are partial perspective views in which the periphery of the cable holder 21 is enlarged. FIG. 10 is a partial perspective view of the cable holder 21 and its periphery as seen from above. FIG. 11 is a view of the cable holder 21 and its periphery viewed from the lower side, and shows the cable at the end face. FIG. 10 is a schematic diagram in which the branch line 18a and the rib 19 are omitted.

If the cable holder 21 is not provided, there is a risk that when the worker assembles the vehicle-mounted antenna device 10, the camera cable 18 contacts each part of the antenna and the antenna element installation position changes. Specifically, when assembling the vehicle-mounted antenna device 10, the camera cable 18 is connected to the camera 60 through the inner case 20. Thereafter, the camera 60 is attached to the inner case 20. After the camera 60 is attached to the inner case 20, the inner case 20 is fixed to the antenna base 30 and the camera cable 18 is pulled out from the cable hole of the vehicle connecting portion 36. Here, when the camera cable 18 is pulled out from the cable hole, the camera cable 18 may come into contact with various antenna elements. If the installation position of the antenna element is shifted due to contact, the electrical characteristics of the antenna may change from the design value. Therefore, it is necessary to disassemble the vehicle-mounted antenna device 10 in the middle of assembly and check whether there is an abnormality in each part of the antenna, and in some cases, it is necessary to replace parts or adjust the installation position of each part.

In this embodiment, a cable holder 21 for isolating the wiring position of the camera cable 18 from the antenna 50 is provided. For example, the cable holder 21 can be inserted with an antenna cable or a camera cable 18 and attached to the antenna base 30 so as to cover a cable hole formed in the antenna base 30. The cable holder 21 is provided with a partition wall 21a. Thereby, for example, when the operator pulls out the camera cable 18 from the cable hole, the camera cable 18 comes into contact with the partition wall 21a of the cable holder 21 and is pulled out from the cable hole. For this reason, it can prevent that the camera cable 18 contacts an antenna element. Further, even after the assembly is completed, the cable holder 21 ensures the distance between the camera cable 18 and the antenna element. For this reason, even after the vehicle-mounted antenna device 10 is attached to the vehicle 3, it is possible to prevent the camera cable 18 from coming into contact with the antenna element and to suppress a decrease in the electrical characteristics of the antenna 50.

In addition, when the cable holder 21 is mounted on the antenna base 30, a first area through which the

antenna cables

26 and 27 can be inserted and a second area through which the camera cable 18 can be inserted by the partition wall 21 a and the cable hole. Form. In the example shown in FIG. 11, the wall which further divides | segments a 1st area | region is formed, and the two

antenna cables

26 and 27 show the case where the cable hole is penetrated. Thus, by forming the first region and the second region, it is possible to secure insertion spaces for the

antenna cables

26 and 27 and the camera cable 18. As a result, for example, even when the camera cable 18 is inserted after the

antenna cables

26 and 27 are inserted, the camera cable 18 can be inserted smoothly and safely without touching the

antenna cables

26 and 27.

Further, when the cable holder 21 is not provided, for example, the antenna base 30 needs to be divided in order to form a first region through which the

antenna cables

26 and 27 can be inserted and a second region through which the camera cable 18 can be inserted. is there. In the present embodiment, by providing the partition wall 21 a in the cable holder 21, it is possible to form the first region and the second region without dividing the antenna base 30. Further, since it is not necessary to divide the antenna base 30, the degree of freedom of the arrangement position of the camera 60 is increased.

[Modification]
As mentioned above, although an example of the embodiment to which the present invention is applied has been described, the form to which the present invention can be applied is not limited to the above-described embodiment, and the addition, omission, and change of the components can be appropriately made.

[Modification 1]
For example, in the above-described embodiment, an example in which only one antenna 50 is mounted is shown, but a configuration in which a plurality of antennas are mounted is also possible.

[Modification 2]
In the above-described embodiment, an example in which the shooting direction of the camera 60 faces the rear of the vehicle in a state where the vehicle-mounted antenna device 10 is mounted on the vehicle has been described. However, for example, a vehicle-mounted antenna device 10B illustrated in FIG. The antenna device 10 may be configured to face the front of the vehicle with the vehicle 3 mounted. The capacity loading element 70 </ b> B in the configuration is configured by reversing the configuration of the capacity loading element 70 of the above embodiment.

[Modification 3]
In the above embodiment, an example in which the first portion 76 of the capacitive loading element 70 is designed so as not to overlap the camera 60 when viewed from the side is shown. However, depending on the degree of electromagnetic influence from the camera 60, the first portion 76 may partially overlap the camera 60 when viewed from the side, as in the capacitive loading element 70C of the in-vehicle antenna device 10C shown in FIG. Good.

[Modification 4]
In the above embodiment, the capacity loading element 70 has been described as a meander shape as a whole. More specifically, the right element 71 and the left element 72 have been described as having a meander shape. However, the right element 71 and the left element 72 may have a plate-like body instead of the meander shape. Furthermore, a configuration in which the right element 71 and the left element 72 that are plate-like bodies and the element connecting portion 73 are integrated is also possible.

[Modification 5]
In the above-described embodiment, the capacitive loading element 70 has a longitudinal direction at a position separated from the camera 60 so that a part of the capacitive loading element 70 overlaps the camera 60 when viewed from the top, but does not overlap the camera 60 when viewed from the side. Is described as being provided along the optical axis direction of the camera 60. The separation distance between the capacitive loading element 70 and the camera 60 can be determined as appropriate. The shape of the capacitive loading element 70 can be determined based on the separation distance.

FIG. 14 is a diagram showing the relationship between the distance d between the capacitive loading element 70 and the camera 60 and the horizontal plane average gain of the in-vehicle antenna device 10 with respect to the FM waveband noise. Since the installation position of the capacitive loading element 70 and the camera 60 in the in-vehicle antenna device 10 is fixed, the shape of the capacitive loading element 70 is changed as shown in FIG. 15 based on the separation distance d shown in FIG. Specifically, the shape of the capacitive loading element 70 was changed so that the separation distance d was 5 mm, 10 mm, 15 mm, 20 mm, and 25 mm. However, the shape of the capacity loading element 70 when the separation distance d is 25 mm is not shown. The separation distance d is the shortest distance between the capacity loading element 70 and the camera 60 as shown in FIG. This is the shortest distance determined three-dimensionally from the positional relationship between the capacitive loading element 70 and the camera 60. “With camera” in FIG. 14 is a state in which the camera 60 is installed and the camera 60 is activated. “No camera” means that the camera 60 is removed, and the shape of the capacitive loading element 70 is the same as “with camera”. In FIG. 14, the camera cable 18 of the camera 60 is described as a coaxial cable not including a magnetic material, but the camera cable 18 may be a magnetic material cable. The camera cable 18 is connected to the ground.

As shown in FIG. 15, the shape of the capacitive loading element 70 was changed so that the area of the capacitive loading element 70 decreased as the separation distance d increased. For this reason, as shown in FIG. 14, the antenna sensitivity decreases as the separation distance d increases. Specifically, the antenna sensitivity is comparable when the separation distance d is 15 mm, but the antenna sensitivity is lowered when the separation distance d is 20 mm or more.

Also, the difference in antenna sensitivity between “with camera” and “without camera” is within −1.1 dB when the separation distance d is 15 mm or more, but exceeds −1.1 dB when the separation distance d is 10 mm or less. That is, by setting the separation distance d to 15 mm, the antenna sensitivity can be made substantially the same as when the camera 60 is present or not. Therefore, it is desirable that the shortest distance between the capacitive loading element 70 and the camera 60 be at least 15 mm apart.

[Modification 6]
In the above embodiment, the antenna 50 has been described as receiving the AM / FM waveband, but the embodiment is not limited to this. The antenna 50 may be, for example, an antenna that receives a DAB (Digital Audio Broadcast) waveband. In this case, the shape of the capacitive loading element that receives the DAB waveband has the same shape as the capacitive loading element 70 of the above embodiment. Since the DAB wave band has a higher frequency band than the AM / FM wave band, the size of the capacitive loading element that receives the DAB wave band can be made smaller than the size of the capacitive loading element 70 of the above embodiment. . For example, a capacitive loading element that receives a DAB waveband has a longitudinally spaced position apart from the camera 60 so that part of the capacitive loading element overlaps the camera 60 when viewed from the top, but does not overlap the camera 60 when viewed from the side. The direction can be provided along the optical axis direction of the camera 60. When the capacitive loading element that receives the DAB waveband is divided into a short-distance side portion and a long-distance side portion based on the distance from the camera 60, the short-distance side portion has a first portion and a second portion. . The first part overlaps the camera 60 when viewed from above, but does not overlap the camera 60 when viewed from side. The second part is located on the vehicle front side of the first part and does not overlap the camera 60 in either a top view or a side view. And the 1st site | part is set so that the length of a height direction may become shorter than a 2nd site | part.

FIG. 16 is a graph showing the characteristics of the horizontal plane average gain in the vehicle-mounted antenna device in which the capacitive loading element 70 of the above embodiment is replaced with a capacitive loading element that receives the DAB waveband. A solid line shows the gain by the vehicle-mounted antenna device having the capacitive loading element that receives the DAB waveband. A broken line is a comparative example. The comparative example is a capacitive loading element having a configuration in which a portion corresponding to the first portion of the capacitive loading element that receives the DAB waveband overlaps the camera 60 in both a top view and a side view. In FIG. 16, the camera cable 18 of the camera 60 is described as a coaxial cable not including a magnetic material, but the camera cable 18 may be a magnetic cable. The camera cable 18 is connected to the ground.

An in-vehicle antenna device having a capacitive loading element that receives a DAB waveband is designed so that it is as far away from the camera 60 as possible, and a portion that overlaps the camera 60 is as small as possible when viewed from the top or side. Yes. As a result, the electromagnetic influence by the camera body 62 that is provided on the outside with the metal housing 64 provided is reduced, and the horizontal plane average gain is higher than that of the comparative example at a frequency of 190 MHz to 228 MHz indicated by the horizontal axis of the graph.

DESCRIPTION OF SYMBOLS 10 ... Vehicle-mounted antenna apparatus 12 ... Outer case 18 ... Camera cable 20 ... Inner case 30 ... Antenna base 50 ... Antenna 57 ... Antenna board 60 ... Camera 62 ... Camera body 64 ... Metal housing 70 ... Capacitance loading element 71 ... Right element 72 ... Left element 73 ... Element connecting part 74 ... Far distance side part 75 ... Short distance side part 76 ... First part 77 ... Second part

Claims

An antenna,
A camera,
A case for housing the antenna and the camera;
With
The antenna has a capacitive loading element provided at a position away from the camera,
When the capacitive loading element is divided into a short-distance side portion and a long-distance side portion based on the distance from the camera, the capacitive loading element overlaps the camera in a top view and / or a side view among the short-distance side portions. One part has a shorter length in the height direction than the second part that does not overlap the camera in a top view and / or a side view.
In-vehicle antenna device.
The capacitive loading element is disposed in a direction in which the longitudinal direction is along the optical axis direction of the camera, and the length in the longitudinal direction of the capacitive loading element is longer than the length in the longitudinal direction of the camera.
The in-vehicle antenna device according to claim 1.
The capacitive loading element has a meander-like wiring shape in which meandering is repeated in the longitudinal direction, and the parallel direction of the meandering parallel wiring is arranged in a direction along the height direction.
The in-vehicle antenna device according to claim 1 or 2.
The first part is formed so that the length in the height direction is gradually shortened as the distance from the second part increases.
The in-vehicle antenna device according to any one of claims 1 to 3.
In the first position and the second position of the first part, the first position is relatively closer to the second part than the second position, and the length of the first position in the height direction is the first position. Longer than the height of two positions,
The in-vehicle antenna device according to any one of claims 1 to 4.
The capacitive loading element is provided at a position higher than the camera,
The in-vehicle antenna device according to any one of claims 1 to 5.
An inner case accommodated in the case;
The capacitive loading element and the camera are disposed in a space between the case and the inner case,
The in-vehicle antenna device according to any one of claims 1 to 6.
The camera is a camera that captures the rear of the vehicle when installed on the roof of the vehicle,
The first part is on the vehicle rear side with respect to the second part,
The in-vehicle antenna device according to any one of claims 1 to 7.
The camera has a camera body and a metal casing that houses the camera body.
The in-vehicle antenna device according to any one of claims 1 to 8.
The camera cable includes a magnetic material,
The in-vehicle antenna device according to any one of claims 1 to 9.
The camera cable has an outer conductor connected to the ground,
The vehicle-mounted antenna device according to claim 10.